A track is a line on the record carrier to be followed by a scanning device and having a length of the order of a characteristic dimension of the record carrier. A track on a rectangular record carrier may have a length substantially equal to the length or width of the record carrier. A track on a disc-shaped record carrier is a 360.degree. turn of a continuous spiral line or a circular line on the disc.
This type of record carrier including associated apparatuses is known from the Japanese patent application no. 06338066. The record carrier described therein comprises first and second alternating servo tracks in the form of adjacent grooves in a substrate. The first servo tracks are frequency modulated at a relatively low frequency, the second servo tracks are frequency modulated at a relatively high frequency. On scanning the record carrier, the scanning device switches between the low and high frequency when changing from one servo track to the next servo track.
The conventional record carrier has the disadvantage that the two frequencies must have a relatively large difference, or frequency guard space, to be able to separate them in the scanning device and thereby create a low cross-talk between the servo tracks. Hence, the total bandwidth of the low-frequency range, the guard space and the high-frequency range is relatively large. However, the total bandwidth should be small to avoid interference with the information recorded in the marks. Moreover, a frequency-modulated signal gives more triangle noise at increasing frequency, making it necessary to increase the bandwidth of the high-frequency range or increase its track modulation to reduce the noise.